Landing stabilizer for aircraft



Oct. 2,1945. I SPIVEYGIE4LYX 2,385,850

I LANDING STABI-LIZER' 316R AIRCRAFT v Filed A i l' '10, 1942 2 s hetets-sne t 1.

I lNVE-NTOR."

12m; sp w? Q Patented Oct. 2, 1945 UN [TED STATES PATENT}f-OF'F'IICE? 385,850 I v q LANDING STABI'LIZER- Fon y Jacob Splegel, Philadelphia, Pa. Application April 10, 1942, Serial No. 4313,;75 1

7 Claims. (01. 244-93) The present invention relates to certain new and I useful improvements in aircraft and itYrelates more particularly to novel stabilizing means for use during landing of fixed-wing heavier-thanair craft.

The operation of fixed-wing heavier-than-air craft presents certain difficulties which tend to limit the usefulness thereof. Fixed-wing heavierthan-air craft, as is well known, are sustained in flight by the differential pressure above and below the wings thereof-such pressure, in turn being created by the forward movement vof-the aircraft. Thusthe aircraft must, at all times, maintain a minimum forward speed in order to keep' it responsive to the controls and to sustain it in flight. This minimum forward speed varies, of course, with the size and type of the. aircraft but, in all cases, is appreciableeven the lightest and smallest of aircraft having aminirnum operating speed of approximately 60 miles per hour.

It is apparent, therefore, that a fixed-wing heavier-than-air craft must. land at a considerable speed ranging from 40 miles per hour upward, even where wing flaps are used. Presenttype fixed-Wing aircraft, when landingatthis speed, necessarily require-a run of at least several hundred feet before they can be halted safely. In present-type fixed-wing aircraft it is impractical to attempt to reduce this run by. braking the Wheels since the forward momentum of. the craft would cause it to nose over or to groundloop with the resulting danger to the aircraft and to the pilot and other occupants thereof An object of the present invention is toprovide stabilizing means for more safely landing a fixed-wing aircraft within a. shorter distance.

Another object of the present invention is to provide means whereby the center of gravity of the fixed-Wing aircraft can be shifted during the landing operation in order to permit braking. of the Wheels and, at the same time, to prevent nosing over Still another object of the present invention is to provide means for changing the center of gravity of a fixed-wing aircraft rearwardl'yduring a landing operationthe amount of shifting or trimming being controlled by, and varied. at the will of, the operator.

With the above and other objects and advantages in view as will be apparent in the following specification, appended claims. and accompanying drawings, the present invention comprises certain novel features and details of construction as will be fully brought out hereinbel owl For the purpose of illustrating the inven 1on,1 thereis shown in theiaccoinpanying' drawingsone form thereof- Which'is at present. preferredgsince the same has been foundjin practice to g'ive satise,

factory and reliable results,- although itisyto be understood that thevarious vinstrum'ent alitiefs of which the. invention consistscanine variously arranged and organized andthatithe inventiori is not limited to thej reci .arrarl ements and organizations of the instrumeritalities 'as here'in shown and described; j H Ref r g. to the .i accompanyin drawings in which like reference characters indicatelike parts throughout: g Figure 1 represents a. fragmentary perspective View of .an' aircraftfembodying thepresent in ventionparts being broken away better Ito. re.- veal the construction thereofr Figure 2 represents a perspectivevmw. one somewhat ar ed scale f one.'of.-,.t.he shift able weights shown in Figure Figure .3 representsa cross-.sectiona'lview gen:

erally along theline 3 -3-o:f Figure 2.; V Figure irepresents-a fragmentary side ele I tional viewof the. shiftable, weight and the. track shown in .F igure .1-the weightbeing Show); in solid lines as it appears during-operation ofthe aircraft, and being shown in dottedlinesas itQappears during landing of the aircraft. .1 Figure 5 represents a fragmentary elevafilim tl viewshowing the shiftable we igfhtiand the.release mechanism .as it appears-at .theQmoment. the weight is released. if .j Figure- 6 vrepresents .a cross-sectional vi ew gen erally along the line 6+6 .of Fig'ur'e 4L showing the. means for retaining thenweightin its reare most position and showing the. indicating'elea tric switch. T In one embodiment. .ofthe'. present inven I may. provide a fixed-wing aircraft. i, generally by the numeral). The -aircraf; as shown inLEigure,.1, .is ar't'ractiomtype Wing monoplaneof generally conventiona struction having a fuselage l l, in which are' disposed 'a' forward ll')'ull' h.ea.d, l2, acentralnbullg head I 3 and arearmost bulkhead I4 ,.the bul-k,- heads conforming to the frearwardlytapered fuselage. section. I v a The traction. propeller of the;.-aircr ft} 15 9f conventional construction, and sisidriven by a conventional powerplant (notshown). installed preferably inthe nose of the plane, 'in front act the cockpit. 2 i "I The. aircraft, l0- is,-,providee lf ;withi afcbnakin-g tracks by a locking device.

system of conventional construction (not shown) 7 whereby the wheels may be braked upon land- Each of the tracks l5, l6 and I1 is of gener by a light cable 36 attached thereto, the arms '33 and 34 are free to swing open and thereby to permit the hinged lower trough-like member ally enclosed rectangular cross-section slotted;;v=.

at the bottom as at 25 and with inturfied flanges l8. The tracks may be of light weight metalalloy or any other suitable material.

The tracks are preferably inclined '56 tha't' when the aircraft I0 is on the groundthe for-.1.

ward end of the tracks will be appreciably higher than the rearmost end thereof. a M T v Weights indicated generally. by the reference characters I9, and 2| are slidablysuspended from the tracks l5, l6 and 11 respectively.

'Each of the weights I9, 20 and 2| includes spaced pairs of rollers 22 mounted within the tracks l5, lE-and l1 and capable of rollingfreely therealong. Therrollers 22 are connected by axles 23 from which a generally fiat panel 24v extends downwardly through the slot 25. The weight is of generally cylindrical form having a central core ZBwhichmay beer leador other heavy weight-giving material. The core, 25 is enclosed by a jacket 21 whichmay be of' canvas orother durable flexible material filled with sand 28, to give a yielding and shock absorbing outer surface. The jacket 21is fastened tothe lower'protruding edge of the panel 24 by any conventional means as for example byrivets 29.

It is apparent that when the aircraft is restingupon the ground, as shownYin Figure 1, ,.the

3f to drop and thereby to permit the slidable Weight to run downward and rearward along the track.

The member 3! may be provided with an upwardly extending lever 31disposed in front of the slidable weight so that the dropping 'of the mem er; 3 F'WiIIQaLISe thelever .31 thereofito push "said weight" rearwardlyas "shown' in Figure 5.

This positive pressure augments the normal tendency of the weight to slide rearwardly and vis .suflicientito overcome 'any possible tendency ofthe weight to" remain in its forward position duetost'icking or freezing? of the rollers 22. .The ,cable 22 attached to the cotter pin 35 maybe passed over a pulley 38 and may extend through a suitable opening 39 in the. forward bulkhead l2 to the instrument board 40 in the cockpit.

'A length of rigid tubing 4! may enclose that portion of'the cable 36 which is in the cockpit in order to prevent accidental displacement of tracks l5, l6 and I! will be incline'dso'thatlthe weights I9, 20 and 2| would normallyrun down to the rear end of the tracksv upon their rollers 22 unless retained at the forward end of the In thedrawings, Ihave fish own one form of 7 lockin'gdevice for retaining the weights atithe forward end of the tracks and'forjreleasing said weights when desired. 1 V

Each of the retaining means includes a. pair mounted as at 32 adjacentsaidlforwardibulke head I2. The member 3| is jadapted, to "de- 'formingly support the lower surface of thej can of curved panels 30 which maybe riveted or said cable. lhe cable .36 terminates in a suitable hand.le adjacent the instrument board 49 whereby said ca-ble can be pulled by the pilot to release the cotter? pin 35 and thus to release the slidable weight-handles 42, and 44 being provided to release weights I9, 20 and 2 respectively. V

A small spring 5 may be provided so as nor mally to retain the cotter pin 35 within the.

aligned'openings in'the arms 33 and 345 and to prevent accidental slipping out of said cotter pin 35.' When, however, the cable 35 is pulled by the pilot, the cotter pin 35 is withdrawn against the action of the spring A5 .to release the arms 33 and 34 and the member-3| and thereby to frnove the slidable weights 'rearwardly.

'Means are also provided to retain the slidable weights at the rear ends of the tracks. The retaining; means may include a plurality, as for example 3, of spaced spring clips or vjaws or fingers 45 mounted upon the 'rearmost bulkhead l4. The clips 46 are disposed; below eachof the tracks 15,16 and I! in position to receive the slidable .7 weights when said weights reach the rearmost ends'of theirrespective tracks. The clips lfi are preferably transversely corrugated whereby they deform the canvas jacket 2'! and more, firmly retain the weight in its rearmost position;

a A safety 'catch' 43 is pivotally' mounted; upon the fupper'side of the track in such a way asto' permit the rollers 22 of the Weight to slide rear- 'wardly ,past' the catch 38 but to prevent said 7 V rollers and said weight from accidentallysliding forwardly, asmight otherwise be the case should the'aircra'ft' nose downward. A small s pring 49 holds the catch 43 in its obstructing position. A

c release cord 59 may be attached to the 'catch vas jacket 2 as showri particularly in FigurejB.

' When the arms 33fand i l are in'their 'closed p0 sitiqnfthey operate to retainth 'slidableweighl in its forward position When,,howeverQ the cotter pin is pulled'free' 'of the smear: and 34 48 whereby said catch my be opened to the positionis'hown in dotted lines in Figure 4 when it isdesired to move the weight to the forward end of the tr'afck.

A'rope 5i is-attached tothe forward end of the canvas jacket 2'i1and passes through a slot lflinthe lever-'3'! and through an opening in the forward bulkhead l2. :The rope 5i 'passesover a'reel or pulley 52 an'd terminates in'a handle 53 wherebythe shiftable weight can' be pulled to its ferwardfposi ion after the landing has been completed. r

A switch indicated generally by the reference character 54 is disposed at the rear end of each of the tracks [5, l and I1 respectively. The switch 54 includes a fixed contact, 55' and a m'oveabl'e contact Bit-the moveable contact 56 being car ried by a plunger 51' which is normally held inits extended position by a'coil spring 58. When the plunger 51 is in its extended position, the switch is open. When, however, the moveable weight slides to the rear end of the track, it forces the plunger 5'! inward until the moveable contact '56 abuts the fixed contact 55 so thatthe switch is closed. Suitable wiring leads from the switch 54 to a source of electricity, as for example a battery or a generator, and an indicating electric hght bulb upon the instrument board 40-indicating'bulbs 60, 6! and 62 corresponding to weights I9, and M respectively. When each of the slidable weights is in its rearmost position, its switch will be closed, its circuit will be com pleted and its corresponding indicating bulb will be lit. 'In this way, the pilot will be enabled to tell at a'glance whether or not the several weights are in their rearmost position. I The operation of my novel stabilizing device will now be described.

The three weights I9, 20 and 2! are normally in their forward position as shownin Figures 1 and 2, in which they are held firmly by the arms 33 and 34 of the member 3! and the panel respectively. The weights [9, 20 and 2| are kept in their forward position during take-oif and during normal flying. v I

During a -landing operation, however,' the weights are intended tobe shifted to their rearmost position inorder' that the center of gravity of the plane is shifted appreciably rearwardly'and so that the tail of the plane becomes substantially heavier whereby nosing over is prevented. When the center'o'f gravity is thus shifted rearwardly and when the tail ofthe plane is made substantially heavier, it is possible to brake the wheels of the aircraft without the danger-(which would otherwise be imminent) of having the plane nose over. In this way, the plane can'be brought to a halt in a fraction ofthe space which otherwise is required to-land aplane whichfcannot be so braked. f f

When the pilot brings his plane in toland, he proceeds in the usual way except that, as soon as his wheels touch the, ground, he pulls the han dies 42, 43 and 44 operating the cables 36 and releasing the cotter pins whereby the weights t9, 2!! and 2| are moved to the rear end of the tracks l5, l6 and H andare retained there by the spring clips 46. The spring clips .45 serve the additional function of cushioning the shock and preventing the sliding weights from damaging the frame of the plane. Rollers 22 pass the safety, catch 48 which is .immediatelyforced back by its spring 49 to the locked position thus preventing accidental return of the, weights. As'so'o'n as the weights I 9, 29 and 2| are seated within the spring clips 46 the switches .are closed and the indicating bulbs 60, 6-1 and 62 light up as an indication tothe pilot that the transfer of weight has been effected. In this way,- the-pilot knows that it is safe to apply the brakes to the wheels of the aircraft and to bringthe plane to .an abrupt halt. r

It is, of course, possible for the pilot to release one or two of the shiftable weights instead of all 'where'this is desired. .In'such case, of course, only the corresponding indicatingibulbs would light up upon completionof the transfer of the weights. t

.Afteri'landing has :been' completed, the safety catch 48' is opened by'pulling on the cord 50*and the weights are brought' back; to their forward position by means of the'rope 5|, the pulley 52 andthe handle 53. When the weights are pulled back 'to their forward position the trough-like member 3! is locked in'the position shown in Figures l and 2 by closing the arms 33 and'34 and inserting the cotter pin 35. r

The plane is then-ready to take off and to perform a similar landing operation.

The weights !9, 30 and 2|, in their forward position, .areheld generally at the center of gravity of the. plane. so that they do not afiect the operating'trim oi the plane.

As mentioned ihereinabove, the cables 36 are protected'by the rigid lengths of tubing 4| to prevent accidental release of the weights during flight and prior to landing;

The sand-filled canvas jacket 21 serves as a padding to revent undue stresses upon the frame of the plane and also, by reason of its flexibility, serves better "to retain the shiftable weights in their desired positions.

The embodiment in'the drawings is but one example of the novel stabilizing means of my present invention. Thus, my stabilizing means could be incorporated into other types of fixedwing aircraft of any suitable construction including low-wing planes, multi-wing planes, pushertype planes, 'multi-engine plane's, etc. The tracks could be otherwise installed within the fuselage of the planea'nd other types'of supporting tracks could be used without departing' from the spirit of the present invention. The number of shiftable weights could, of course, be varied with the requirements of theparticular aircraft.

By use of my present invention, it is possible to land a plane in a much smaller landing area and, indeed, in the case of light planes, it is possible to land upon an extremely small area. In fact, by use of my novel stabilizing device, it is possible to land a light aircraft upon'the roof of a building orwi'th-in a small yard or field. It is thus apparent that the range of usefulness of light aircraft is considerably broadened since they can be used for vfamily use or for errands and deliveries within a city without the need forimpractical and costly regulation landing fields.

The novel stabilizing means of my present invention is also adapted for use with military aircraft. Thus,by use of my stabilizing means, militarysaircraft which normallyoperate at extremely high speeds and which, therefore, normally require unusually large landingv areas can be landed safely inconsiderablyzsmaller areas.

My present invention is' also adapted for use with sea-based aircraft such as carrier-based aircraft and sea-planes. Thus, a sea-plane equipped with the novel stabilizing" means of my present invention has considerably less tendency to nose ovenuponlanding than is ordinarily the case. Similarly; a carrier-based aircraft equipped with the novel stabilizing meansof my present-invention is capable of landing upon a relatively small flight deck without the need for. complicated landing devices such as are'o'therwise' required.

The present invention may'be embodied in other specific forms without departing from the spirit or essential attributes'thereof, and his therefore desired that the 'present embodiment be considered in all respects as illustrative and not restrictive,reference bein'g had' tothe ap- "3, In an aircraft havinga fixed wing,ia

pended claims rather than .to the foregoing de- 7 scription to indicate the scope of the invention. The invention having thus been described, what 7 is hereby-claimed to be new and desired to be secured by Letters Patent is:

lgl'nan aircraft having a-fixed wing, a fuselage, a power-plant, a propeller and landing gear, 7 a plurality of rearwardly-sloping' tracks mounted longitudinally 'within said: fuselage, a truck mounted upon each of said tracks and freely movable therealong, a counterweight carried by each of the trucks, independent releasable means for retaining each of the counterweights at the upper'forwa'rd 1 end of its track during normal flying in which position, the counterweights are generally adjacentthe :center of gravity of said aircraft, independent pilot operated means for re leasing each of said retaining means to'permit each of said counterweights to move rapidly to 'lthe rear of the aircraft during allanding opera- :2. In an aircraft having a fixed wing, a fuse- V lage, a power plant, a propeller and landing gear; a plurality of rearwardly-sloping tracks mounted longitudinally' within said fuselage a truck mounted'upon each of said tracks and freely movable therealong, ia counterweight carried by each ofthe trucks, independent releasable means for retaining each of the counterweights at'the upper forward end of its track during normal rapidly to the rear .of'saidaircraft duringa landing operation whereby said aircraft ismade appreciably tail-heavy to prevent nosing-over,

holder to fall open and to movesaid counterweight rearwardly, means; for immovably-engaging said'counterweight at the lower rearward end of said track, and means for braking said landing wheels whereby saidaircraft can be halted withinla'short distance after said counterweight has been shifted rearwardly, g I 4. In an aircraft having a fixed Wing, a fuselage, a powereplant, a propeller and landing wheels, a rearwardly-sloping track mounted longitudinally within saidfuselage, a truck mounted upon said track and freely movable therealong, a counterweight carried by said truck, releasable means for retaining'said counterweight at the upper forward end of said track during normal flying of said aircraft, in which position said counterweight is generally adjacent the center of flying in which position the counterweightsare generally adjacent thecenter of gravity of said aircraft; independent pilot operated means for releasing each of said retaining means to permit each of said counterweights to move rapidly to the rear of the aircraftduring a landing operation'whe reby said aircraft ismade adjustably V tail-heavy to prevent nosing-over, independent means for'immovably' engaging each of said counterweights at the lower'rearwar'd end ofits track, independent electrically-operated indicating sig-' nals for each of said counterweights, and an electric switch adaptedto be operated bylm'ove-' ment of each of said counterweights to actuate the corresponding signal andthereby to indicate the position of saidxcounterweight.

fuse-.- lage a power-plant, a propeller and landing wheels, at rearwardly-sloping track mounted longituclinally within said fuselage, a truck mounted 7 upon said track and freely movablatherealong, a

counterweight carried'by said truck, said counterweight including &a,relatively dense weightgiving coreand apadded jacket surrounding: said core, releasable means for'retaining said counterweight at-the upper forward end of said'track; -during normal flying ofsaid aircraft, iniwhich position said counterweight isgenerally adja cent the center of gravity of said' aircraft; said gravity of saidaircraft, pilot operated means for releasing said retaining means to permit said counterweight to move rapidly to the rear of said aircraft duringa landing operation whereby said aircraft is'made appreciablyrtail-heavy to prevent nosingeover, means for immovably engaging saidcounterweight at the lower rearward end of i 7 said track, said engaging means comprising a plurality of sprin fliawsadapted to 'be spread apart by and to grip said counterweight, and means for braking said landing wheels whereby said aircraft can be halted within a short distance after said counterweight has been shifted rear- 7 wardly.

'5. In an aircraft having a fixed wing, a fuselage, a power-plant, a propeller and I landing wheelsfa rearwardly-slopingtrack mounted 1ongitudinally within said'fuselage, a truck mounted upon said track and freely :movable therealong, a counterweightrcarried by said'truck, releasable A means for retaining said counterweight at the upper; forward endof said track during normal flying of said aircraft, in which position said counterweight is generally adjacent the center of gravity of said aircraft, "said retaining means including a pin-retained pivoted anglerholder' partially enveloping said counterweight, pilot operated means for releasing said retaining means to permit said counterweight to moverapidly to r the rear of said aircraft during a landing operaretaining means including a fixed plate conforml- 7 ingggenerally, to thee-contour of said counterweight and generally adjacent-the upper portion thereof,a pivotedangle holder generally adjacent jthe lower portion .of. said counterweight and hinged arms connecting the rearedges of said I plate and said angleholder and enclosing said 1 counterweight; means for releasing said retaining means toQpermit said-counterweightto move tionwhereby said' aircraft is made'appreciably tail-j-heavy to prevent'f nosing over, said releasing means including a cable attached to the pin holding said angle holder whereby saidpin may be 7 pulled out topermit said angle holder to drop, means for immovably engaging said counter weight at the lower I rearward end of ,said track,

and means I for braking said landing wheels whereby said aircraft can be haltedwithina short distance after *said' counterweight has been I shifted rearwardly."

6. In an aircraft having a fixed wingla fuselage, a power-plant, a propeller and landing wheels, a rearwardly sloping track mounted 1on gitudinally within said fuselage, a truck mounted upon said track and freely molvable therealong, a counterweight carried by said truck, releasable means for retaining said counterweight at'the upper forwardiend of said trackrduring normal 7 flying ofsaid aircraft, in'which' position said counterweight is generally; adjacent the-center of gravity of said aircraft,pilot operated means for the rear of said aircraft, releasable means for releasing said retaining means to permit said counterweight to move rapidly to the rear of said aircraft during a landing operation whereby said aircraft is made appreciably tail-heavy to prevent nosing-over, means for immovably engaging said counterweight at the lower rearward end of said track, an electrically-operated indicating signal, an electric switch adapted to be closed by said weight in its rearmost position thereby to actuate said signal, and means for braking said landing wheels whereby said aircraft can be halted within a short distance after said counterweight has been shifted rearwardly.

7. In an aircraft, a weight adapted for free movement generally longitudinally of said aircraft, said Weight being normally urged toward retaining said weight at a forward position substantially at the normal center of gravity of said aircraft, pilot-operated means for releasing said weight thereby to permit said weight to move rapidly rearwardly of the normal center of gravity of said aircraft, means for immovably engaging said weight in its rearmost position, independent auxiliary locking means for preventing forward movement of said weight from its rearmost position, means operable from the cockpit of said aircraft for releasing said auxiliary locking means, and means operable from the cockpit of said aircraft for returning said weight to its forward position.

JACOB SPI'EGEIL. 

